MINISTRY
 OF
 EDUCATION
 AND
 TRAINING
 


 


 MINISTRY
 OF
 PUBLIC
 HEALTH
 
 

HANOI
 MEDICAL
 UNIVERSITY
 


 MEDIA
 
 

 

 

Specialization:
 Ear
 Nose
 Throat
 
Code:
 62720155
 

 

SUMMARY
 OF
 MEDICAL
 DOCTORAL
 THESIS
 

 

 


Reviewer 3: Assoc. Prof. PhD. ĐOAN HONG HOA
National Otorhinolaryngology Hospital of Vietnam

The Thesis will be protected at the Thesis-level dissertation board:
Hanoi Medical University
At: h

month

date

year

Can find thesis at:
National Library
Hanoi Medical University Library
Central Medical Information Library


THE PUBLISHED RESEARCH WORKS
RELATED TO THE THESIS TOPIC
1. Nguyễn Thị Tố Uyên, Nguyễn Tấn Phong (2012), Kết quả ban
đầu của phẫu thuật tiệt căn xương chũm tối thiểu đường xuyên
ống tai, Tạp chí Nghiên cứu Y học, số 78 (1), tr 48-52.
2. Nguyễn Thị Tố Uyên, Nguyễn Tấn Phong (2013), Kết quả
phẫu thuật tiệt căn xương chũm tối thiểu đường xuyên ống tai,
Tạp chí Nghiên cứu Y học, số 82 (2), tr 64-71.
3. Nguyễn Thị Tố Uyên, Lương Hồng Châu, Nguyễn Tấn Phong
(2017), Triệu chứng cơ năng của viêm tai giữa mạn tính nguy
hiểm được phẫu thuật nội soi tiệt căn xương chũm đường xuyên

development in diagnosis are motivation for improvement in treatment.
With severe lesions on the sclerosis mastoid, small antre, post-auriculair or
antero-auriculair mastoidectomy made a big and safe mastoid cavity which
is too large for lesions with many disadvantages, on this case, the close
technic mastoidectomy is difficult with high risk of complications and will
be dangerous if patients do not return periodic examination and take the
second look surgery when suspected recurrent cholesteatoma.
Antrotomy transcanal under microscope was reported by Holt J.J in
2008. When compare with post-auriculair and antero-auriculair, the
transcanal is the shortest and direct entrance to antre, and well keeping
propre mastoid cortex. Although the endoscopy (1990) was used on ear
surgery much later than micoscopy (1950), it become the usefull
manipulation for endoral and transcanal entrance thanks for small tip and
wide fild. Nguyen Tan Phong (2009), Tarabachi M. (2010) reported
endoscopy transcanal atticotomy, antrotomy. Nguyen Tan Phong (2010),
Tarabachi M. (2013) continue to down the posterior canal wall for the
endoscopic transcanal canal wall down (ET CWD) mastoidectomy. This
operation is addapted with cholesteatoma or grade IV retraction pocket
base on schlerose mastoid and small antre which made a small size of


2

mastoid cavity but ensure control of disease and drainage, rapid recovery
time, high aesthetics, can improve hearing. To improve the theoretical,
indicative, technical contribution to disseminate surgery in ENT specialist
we carry out the topic: “Evaluation of results of endoscopic transcanal
canal wall down mastoidectomy for dangerous chronic otitis media”
with 2 target:
1. Describe the clinical, subclinical characteristics of patients with

view like cholesteatoma. Through reserch decades, many authors agree
with the view that retraction pocket are one of the pathological
mechanisms of cholesteatoma Three characteristics are mobility, selfcleaning, and superinfection that assess the risk of cholesteatoma, with
patches of superficial patches and superinfection showing the highest risk.
1.1.3. The formation and progression of cholesteatoma: the squamous
cell of the inner layer of cover breaks into the centre, accumulates, grows,
and invades the middle ear passively. On the other hand, the outer layer of
the shell produces an enzyme that eats away the bone in an active way,
cholesteatoma can gradually destroy middle ear structures by passive
developing and active destruction of neighboring bone structures.
1.1.5. Clinical characteristics of dangerous chronic otitis media
1.1.5.2. Functional Symptoms: In addition to the classic symptoms can
meet dry ear, mild hearing loss or normal hearing in dry cholesteatoma,
grade IV retraction porket.
1.1.5.3. Physical symptoms: Endoscopy can detect dangerous lesions but
does not measure the extent of the lesion, but the following images are
often present in the
 localized lesions:
Perforation of eardrum: Pars tensa: postero-supperior, marginal or just
below the anteror malleus-atrium ligaments; Pars flaccida: can be erossion
the attic wall (solid bone), sometimes scaly (brown, firmly attached).
Perforation of the attic wall: Spongy bone, which may have granule, pus.
Polyp: usually from attic, characteristic, covered with cholesteatoma.
Grade IV retraction pocket: Pars flaccida: “naturally opened attic”,
 
often. Pars tensa: postero-supperior: can invade the pars flaccida; ½
posterior:
  Easy to skinned the posteiror tympanic cavity, type “faux
perforation”; postero-inferior, anterio-supperior or total are rare.
1.1.6. The paraclinical characteristics of dangerous COM

Endoscopy ear surgery: began at 1990 by Takahashi and Thomassin
J.M., now it's already popular in the world. Nguyen Tan Phong (2009),
Tarabachi M. (2010): transcanal attico-addito-antrotomy. Continue
lowering the facial nerve wall, Nguyen Tan Phong (2010), Tarabachi M.
(2013) had done ET CWD mastoidectomy. Some Vietnamese surgeons
(Cao Minh Thanh, Ho Le Hoai Nhan) also use endoscopy ear surgery for
dangerous COM.
1.2.2. Concept of CWD: destroy postero-superior ear canal wall and attic
wall, unify mastoid, tympanic cavity and ear canal in unique cavity,
lowering the facial nerve wall, meatoplasty; Radical mastoidectomy:
remove the eardrum, malleus and enclume, keep the stape, clamped
eustachian tube; Modify radical mastoidectomy: keep the eardrum,
ossicular chain or tympanoplasty.
1.2.3. The entrance of CWD: 3 types are postaural (drill through mastoid
cortex to antre), preaural (drill at the same time the mastoid cortex and
postero-anterior ear canal) and transcanal (direct drilling at attic wall and
postero-anterior ear canal without removing the mastoid shell).


5

1.2.4. Endoscopic transcanal canal wall down mastoidectomy
1.2.4.3. Anatomical basis of ET CWD mastoidectomy
According to Legent, Ngo Manh Son, Tran To Dung average
mastoid cortex thickness is 12.41 ± 1.6 mm and split wall between antre
and ear canal thickness is just about 2 – 4 mm. Compared to the classic
postaural entrance, transcanal is the shortest access to antre.

1
 

2.1. Research subjects: 54 patients with 57 ears are diagnosed COM with
cholesteatoma or grade IV retraction porket which are performed
endoscopy transcanal canal wall down mastoidectomy at the ENT National
Hospital from September 2010 to September 2013.
2.1.1. Selection criteria
- Patients are diagnosed COM with cholesteatoma or grade IV retraction
porket:
+ Clinical: at least 1 of endoscopic lesions: Pars tensa: marginal
perforation, nacre pus
  or uncontrolled retraction porket; Pars flaccida:
perforation or uncontrolled retraction porket; Erosion of attical wall.
+ Tonal audiograms: no limit of type and level of hearing loss but
does not include progressive lesions of cochlear or auditory nerve or
intracranial.
+ CT Scan: Translucent blocks or hollow cavity in the middle ear
which erosion bone: ossicular chain, attical wall, middle ear, external
semi-circular canal, fallop; mastoid structure: compact or poor cell (but
compact in facial wall for transcanal entrance, small antre.
+ Evaluation in operation: local lesion, solid mastoid, small antre.
- Be done ET CWD mastoidectomy, followed and evaluated post-op.
- Patients and caregivers (if ≤ 18 years) agree to participate in the study.
2.1.2. Exclusion criteria: are in inflammatory or dangerous complication
such as meningitis, brain abscess, atrial fibrillation… ; have deformed
outer ear, middle ear; don’t follow up until the operation stable, not
evaluated at 3 months post operation.
2.2. Research methods
2.2.1. Research design: prospective, intervention.
2.2.2. Choose a convenient template: There were 54 patients with 57
diseases ears, 3 patients were bilateral operated. All 57 ears were evaluated
at 3 months; 50/57 at least 1 year of follow up.

and hypotympany, applied 4 types tympanoplasty but instead of the
eardrum covering the entire tympanic cavity, on the CWD mastoidectomy
the tympanic membrane cover only the middle and hypotympany (small
tympanic cavity) because the attic be opened into the ear canal with
additus and antre. Type I: miryngoplasty; type II, III: + reconstruction
ossicular colume; type IV: form the mini tympan for hypotympany
(including round windows and Estachian hole)..
Materials for eardrum reconstruction: reusing the eardrum – canal
flap or shaping the eardrum at cartilage, pericartilage, temporal fascia.
Material for ossiculair reconstruction: the ceramic biological or
mastoid bone or cartilage fragments (don’t reuse incus or malleus because
of remnent cholesteatoma or retraction pocket). The chain will remain if
it’s continuous, good mobility and ensure complete removal of the pocket.
Place ventilation tube: tympanoplasty but suspected function of
Eustachian tube.
Clog up Eustachian hole: when dermatitis all the hypotympany.


8

Meatoplasty: drilling process in CWD mastoidectomy was enlarged
the ear canal bone. When soft ear canal is narrow, the incision in the roof
makes it wider, that is “outer cartilage meatoplasty”.
2.2.4.3. Evaluation of surgical results
* During surgery: Detailed records of lesions, injury of bone chain, attic
wall, middle ear roof, canal semicircular and the VII; mastoid structure,
antre size, antre bottom position. Difficulties and advantages.
* Postoperative period: Monitoring complications: wound infection,
vestibular disorders, facial nerve peripheral paralysis... Monitor the
recovery of operation cavity.

Pars tensa: perforation marginal, late white pus/ uncontrolled retraction pocket.
Attical walls: erode or perforation.

Tonal audiometry:
3 type of hearing loss

Temporal bone CT Scan:
- Blurred or hollow cavities erode ossicular and
the middle ear bone.
- Local lesions in tympany, attic, additus, antre
- Mastoide ivory or poor cellular, small antre.


 

ENDOSCOPIC TRANSCANAL CANAL WALL DOWN MASTOICDECTOMY

Accessement cavity middle and lower atrium in PT: longer cholesteatoma or not

 
No longer

Cholesteatoma at oval window
 

Tympanoplasty type I, II, III

Cholesteatoma at Eustachian tube

Tympanoplasty type IV

31.6%
(n=18)

73.7%
(n=42)

68.4%
(n=39)

26.3%
(n=15)

0%
Otorrhea

Tinnitus
Yes

Dizziness

24.6%
(n=14)

75.4%
(n=43)

Earache

No


57
%
50.9
22.8
8.8
12.3
5.3
100


11

Table 3.6. Rate of attical and postero-superior canal wall damage
Ear
Corroded
Corroded posteroHard to
Normal N
canal attical wall
superior wall
judge
n
44
1
8
4
57
%
77.2
1.8
14.0

ear canal. On operation, antral bottom were compared to floor of ear canal:


12

92.3% higher, 7.7% at the level of floor and no case is lower. Some antral
bottom at the level of 1/3 middle and most at the level of 1/3 inferior of the
canal on CT scan were equal canal floor on operation, p < 0.01.
* Narrow mastoid entries:
Meninge down low: 29.8% higher or at the level of the roof of
middle ear (Figure 3.1); 56.2% lower than the roof of middle ear (Figure
3.2); 14% close to the top edge of ear canal (Figure 3.3).

Figure 3.1.(Pt No.16)
Figure 3.2.(Pt No. 3)
Figure 3.3.(Pt No. 41)
Sigma sinus encroachment forward: on axial slices: 68.4% vein
located behind the antre (Figure 3.4); 17.6% at the level of antral posterior
edge (Figure 3.5); 14% front of antral posterior edge (Figure 3.6).

Figure 3.4.(Pt No. 13) Figure 3.5.(Pt No. 3) Figure 3.6.(Pt No. 28)
3.2. Results of endoscopic transcanal canal wall down mastoidectomy
3.2.1. Surgical procedure:
3.2.1.3. Bone damage on operation: all the ear suffered from with varying
degrees: 96.5% of bone chain were worn, of which 68.4% were
discontinuous, 28.1% were continuous; 3.5% chain integrity but rigid
joints. The most abrasion was incus 94.7%; followed by malleus 68.4%;
At least 31.6% of stapes (exept the food).
3.2.1.4. Middle ear reconstruction
Table 3.21. Rate of middle ear reconstruction

inflammation.
3.2.2.2. Evaluation in the postoperative period
Inflammatory exudate flow time:
77.2%
N = 57
(n=44)
8.8%
10.5%
3.5%
(n = 5)
(n=6)
(n=2)

No otorrhea

1 week

2 weeks

3 weeks

Figure 3.23. Time distribution of inflammatory exudate post-op
Covered cavity time: Average: 5.44 ± 0.14 weeks. The earliest is 4
weeks (12/57 ears ≈ 21.1%) and the latest is 8 weeks (1/57 ears ≈ 1.8%).
3.2.2.3. Evaluation post-op over a year: All 54 patients with 57 ears
examination regularly in 2 - 3 months until the operative cavity is stable,
then 47 Bn with 50 ears involved full schedule of at least 1 year, N = 50.
Telephone conversations with 7 patients were not re-examined: any case
have ottorhea or discomfort, 4/7 ears improved hearing.
Long terme follow-up: 35.1 ± 9.3 months ≈ 3 years, (12 - 50

(n=39)
(n=36)
24%
6%
6%
(n=12)
(n=3)
(n=3)
0%
Tinitis

Dizziness

Earache

Figure 3.26. Prevalence of pre-op and post-op functional symptom
- Endoscopic examination:
+ Status of radical mastoidectomies cavity:
58%
N = 50
(n=29)
24%
16%
(n=12)
2%
0%
(n=8)
(n=1)
(n=0)
Propre

PTA post-op: good results (11 - 20 dB) 8.8%; pretty (21 - 30 dB):
26.5%; Poor (31 - 40 dB): 17.6% and very poor (PTA> 41 dB): 47%.
Table 3.31. Evaluation of PTA by pre- and post-op value range in types
I, II, III
PTA
Pre-operation
Post-operation
n % Accumulative n % Accumulative
N
%
N
%
11 – 20 dB
3 8.8
3
8.8
21 – 30 dB 9 26.5
9
26.5
9 26.5 12
35.3
31 – 40 dB 5 14.7 14
41.2
6 17.6 18
52.9
41 – 50 dB 1 2.9
15
44.1
6 17.6 24
70.6

7
20.6
7
20.6
17 50.0 17
50.0
21 – 30 dB 12
35.3
19
55.9
7
20.6 24
70.6
31 – 40 dB
9
26.5
28
82.4
6
17.6 30
88.2
41 – 50 dB
4
11.8
32
94.1
4
11.8 34
100
51 – 60 dB

children, at least 16 years of age. The oldest is 71 years old (second ear
surgery at 73 years old). ET CWD is applicable in elderly patients.
Opposite ear: 50% were or are at risk of dangerous COM, reflecting status
of eustachian tube and nasopharynx, affects to surgery indication.
4.1.2. Functional symptoms: Even if symptoms are not adequate, atypical
cholesteatoma need to examine and find dangerous COM. No otorrhea
5.3%, translucent fluid 20.4%, ear flow not rotten 42.6%; not dizzy 73.6%;
no pain 24.6% ....
4.1.3. Pre-op endoscopy: at least one dangerous lesion of the three sites:
the most common were pars flaccida with 93% (50.9% cholesteatoma,
21.1% grade IV, 12.3% polyps, 8.8% dark brown scales and tend to erode
attical wall (77.2% sure, 14% suspected), only a few have dangerous
lesion in pars tensa (10.5% cholesteatoma, 1.8% polyp cover, 17.5%
reduction in IV). It can be said that most ear infections cholesteatoma or
grade IV were selected to apply ET CWD with lesion in attic.


17

4.1.4. Preoperative Hearing
4.1.4.3. Pre-op PTA: conductive hearing loss group: 40.6 ± 13.7 (slight),
mixte hearing loss group: 59.6 ± 12.4 dB (moderate).
4.1.4.4. Pre-op ABG: conductive and mixte hearing loss group: 32.5 ±
11.6 dB (discotinuos COM of Cao Minh Thanh is 42.19 ± 7.69).
Cholesteatoma and grade IV retraction pocket often go together with slack
pars tensa, when the ossicular chain is interrupted the membranes will
touch on the rest of chain and leading to the transmission of sound. As
such, dangerous COM with ABG < 35 dB still has discontinous chain.
4.1.5. Temporal bone CT Scan
4.1.5.1. The role of CT Scan in the diagnosis of dangerous COM: a

designate the ET CWD mastoidectomy for the cases which antre is
smaller, equal or slightly larger than the ear canal and the antral bottom
is as high as possible or equal to the ear canal floor level.
* Narrow mastoidectomy entrance: When the mastoid is compact, the
small antre may experience lowering meninge, encroached sigma sinus...
making it difficult for the posterior mastoidectomy entrance.
- Meninge down low: On the Coronal plane, use the middle ear ceiling
and the superior wall of ear canal to compare the position of the meninges.
There are 70% meninges which outside the antre lower than the middle ear
ceiling, and even 14% of them close to the ear canal.
- Sigma sinus encroachment forward: on the Axial plane, an imaginary
line passing through the posterior wall of the antre parallel to the posterior
wall of the ear canal, the sigma sinus as far away from this line means that
more behind the posterior wall of antre, drilling the mastoid as easy. There
are no difficult to apply transcanal entrance for 31.6% of sigma sinus
encroachment forward with 17.6% same lever and 14% crossing this line.
In summary, in the CT Scan that the meninge close to ear canal and
the sigmoid sinus encroache on the front of posterior wall of the antre, the
transcanal radical mastoidectomy with endoscopy is the optimal choice
because of avoiding meninges, sigmoid sinus and still control of lesions.
4.2. Treatment results of ET CWD mastoidectomy
4.2.1. Surgical process
4.2.1.1. Skin incision and meatotomy: 100% of the incision are in the ear
canal make a V skin flap, 33.3% of the incision are pulled to anterior ear
groove for a wider operative view and and also “meatotomy outside the
cartilage”, do not deform the ear, ensure aesthetics, suitable for small
radical mastoid cavity (Va/S rational).
4.2.1.2. Drill technic of transcanal entrance
Advantages of transcanal entrance: expressed in the safety. The posterior
entrance should be noted within the surgical triangle to avoid expose the

Cong Dinh). In order to limit grafted rejection due to inflammatory in the
middle ear, we use cartilage to lay-over the crest of staped and in contact
with the eardrum, it help to supporting and strengthening the eardrum.
Obholzer R. and Becvarovski also reconstruct the acoustic system with
cartilage or eardrums placing directly on the stape.
4.2.2. Follow up the results of surgery
4.2.2.1. Catastrophe and complication: There is 1 case (1.8%) of paralysis
peripheral facial nerve grade 4 which completely recovered after 1 month.
Kos M.I.: 0.3% but failed to recover, Mukherjee P.: 3% with recovered


20

after 2 months. Transcanal entrance is outside of the facial nerve so it
relatively safe. However when lowering the wall should be drill carefully
and pump enough water to avoid heating the nerve.
4.2.2.2. Evaluation in the postoperative period
- Inflammatory exudate flow: 77.2% does not flow. The incidence and
timing of flow was much less than that of the posterior or anterior CWD
technic (thanks to using a small cavity (≈ twice of the ear canal volume).
- Time for skin covering the cavity: over half of cases in 5 weeks and
82.4% in 6 weeks, significantly shorter than other CWD technic. Beside
the small cavity advantage, we use temporal fascia or pericartilage or
cartilage to lining and maximum reuse the ear canal skin flap to cover.
4.2.2.3. Stability of CWD cavity: assessed at 50 ears which follow at least
1 year with functional symptoms, endoscopy, audiometry.
- Postoperative follow-up time: mean 35.1 ± 9.3 months (≈ 3 years, 12 to
50 months), of which 86% followed at least 2 years, more than half (54%)
followed at least 3 years (including 6 ears (12%) over 4 years (Figure 3)).
- Improvement of functional symptoms: relatively clear, pre-op are 94%

- Bone conduction reserve (threshold): with N = 50, almost unchanged
between before and after surgery (deviation of 0.05 ± 8.2 dB with p> 0.05)
so there aren’t inner ear’s complications no damage to the hearing cells.
This result partly confirms the safety of ET CWD mastoidectomy.
- Hearing changes in tympanoplasty type I, II, and III: N = 34,
eardrum reconstruction with ossicular preservation or reconstruction are
initially successful.
Improvement of PTA: The average PTA pre-op is 46.6 ± 16.3 dB
and post-op is 41.3 ± 17.9 dB so PTA improved 5.3 ± 13.5 dB.
PTA evaluation pre-op and post-op according to value range: Table
5, no case less than 10 dB. With the PTA in the range of 11 - 20 dB
(normal hearing): pre-op any case but post-op has 3 ears (8.8%). With
PTA ≤ 30 dB (slight hearing loss, according to Commitee on Hearing and
Equilibrium guideines for the evaluation of results of conductive hearing
loss, patients can integrate into social life without hearing aids): 26.5%
pre-op and 35.3% post-op. PTA ≤ 50 dB (mild hearing loss): 44.1% pre-op
and increased to 70.6% post-op.
Improvement of ABG: ABG
 efficiency 6.5 ± 13.5 dB is not high in
functional surgery but is good at CWD mastoidectomy. Moreover, ABG
30.6 ± 11.1 dB pre-op is not easy to improve so 24,0 ± 9,8 dB post-op is
relatively good.
Looking at table 6, no case with ABG ≤ 10 dB, ABG from 11 - 20
dB from 20.6% pre-op increase to 50% post-op. ABG ≤ 20 dB (considered
good) so over half of cases is successful tympanoplasty. ABG ≤ 30 dB
pre-op is 55.9% and post-op increase to 70.6%. Our hearing efficiency is


22


17.6%, external semi-circular canal 12.3%, 2nd facial nerve 35.1%.
+ Characteristics of mastoid and antre: important for surgical
indications.